Temporal Tables for Data Versioning

-- SQL Server: Create system-versioned temporal table
CREATE TABLE products (
  product_id INT PRIMARY KEY,
  name NVARCHAR(100),
  price DECIMAL(10,2),
  valid_from DATETIME2 GENERATED ALWAYS AS ROW START,
  valid_to   DATETIME2 GENERATED ALWAYS AS ROW END,
  PERIOD FOR SYSTEM_TIME (valid_from, valid_to)
)
WITH (SYSTEM_VERSIONING = ON (
  HISTORY_TABLE = dbo.products_history
));

-- Query data as of a specific point in time
SELECT * FROM products
FOR SYSTEM_TIME AS OF '2025-01-15 10:00:00';

-- Query all versions of a row
SELECT * FROM products
FOR SYSTEM_TIME ALL
WHERE product_id = 42
ORDER BY valid_from;

-- Query changes within a time range
SELECT * FROM products
FOR SYSTEM_TIME BETWEEN '2025-01-01' AND '2025-03-31';